1. Field of the Invention
The present invention relates to an apparatus for assembling a pair of fastener elements of a garment fastener, such as a button, a snap button or an ornament, with a garment fabric disposed between the two fastener elements.
2. Prior Art
U.S. Pat. No. 3,964,661, issued June 22, 1976 discloses a fastener-assembling apparatus which includes a first drive mechanism for vertically reciprocating an upper punch of an upper unit, a second drive mechanism for vertically reciprocating a lower punch or die of a lower unit, a first pusher mechanism having an upper pusher reciprocally driven by the first drive mechanism to supply one of a pair of fastener elements to the upper unit, a second pusher mechanism having a lower pusher reciprocally driven by the second drive mechanism to supply the other fastener element to the lower unit, and an indicator fixedly connected to the upper pusher for directing a beam of light to a garment fabric to indicate a position on the garment fabric where the two fastener elements are to be attached. The drive and pusher mechanisms are operatively linked with each other in such a manner that the upper and lower pushers are retracted from the path of movement of the punch and die in response to the movement of the punch and die in a direction toward each other to clinch the two fastener elements together, with the garment fabric sandwiched between the fastener elements.
The known apparatus of the foregoing construction has various drawbacks, as follows:
The first drive mechanism includes a cylinder slidably supported on the frame and operatively connected with the first pusher mechanism. However, there is no direct connection between supporting means and connecting means with the result an accurate timed operation of the first drive mechanism and the first pusher mechanism is difficult to achieve.
Furthermore, the upper pusher of the first pusher mechanism is operatively connected with the cylinder of the first drive mechanism through a pair of pivot levers linked together with a compression coil spring acting therebetween. When a cylinder tube of the cylinder is axially moved in a direction to advance the upper pusher, the spring-biased pivot levers resiliently move the upper pusher forwardly, thereby preventing abrupt supply of the fastener element to the upper unit. The spring-biased levers, however, do not change the direction of power transmission path extending from the cylinder tube to the upper pusher with the result that the upper pusher is forced to advance the fastener element even when foreign matter is present in an element-feed path. With this forcible feeding, the fastener element is likely to be damaged or otherwise deformed.
Another problem is that the cylinder is slidably supported on a block secured to a frame and is urged by a spring against the block. Upon energization and de-energization of the cylinder, the cylinder tube hits against the block, thereby generating objectionable shock noises and vibration.
It is a further drawback of the known apparatus that the lower pusher and the die are reciprocated by a single cylinder via a linkage mechanism. Both the stroke of the lower pusher and the stroke of the die are depending on the stroke of the cylinder and hence a separate stroke adjustment of the lower pusher and the die is difficult to achieve. With this difficulty, a reliable attachment can not be expected when the fastener elements are to be set on garment fabrics varying in thickness.
Another difficulty is that the position indicator is structurally and operatiionally integral with the upper pusher and hence requires a relatively large operating area. The position indicator is retracted from the path of movement of the punch upon actuation of the air cylinder to lower the punch. It is therefore no longer possible for the operator to monitor as to whether the fastener elements are being set on the garment fabric accurately at the desired position. Further, the indicator has a downwardly projecting portion which would catch a garment fabric as the indicator reciprocates in unison with the upper pusher.
A still further problem is that the known apparatus has no means for retaining an upper unit reliably in a position to receive the fastener element from the upper pusher. Rather, the upper unit is likely to be displaced from the element-receiving position when the stroke of the punch is changed while in use.
Furthermore, the prior apparatus requires a tedious and time-consuming operation for removing foreign matter or a jamming fastener element from the feed path, resulting in downtime of the apparatus.